Zimbabwean activist pastor Evan Mawarire appeared in court on Thursday to be charged with subverting the government, punishable by up to 20 years in jail, after protests this week in which three people were killed and dozens injured.

Mawarire was arrested on Wednesday  and initially charged by police with the lesser crime of inciting public violence after he posted on social media encouraging Zimbabweans to heed a strike call by the biggest labour union.

On entering the courthouse, he told reporters: “None of what I am accused of is what I have done at all. If we have true justice in this country, let’s see it at play.”

The Harare pastor rose to prominence as a critic of former strongman Robert Mugabe and led a national protest shutdown in 2016. He was tried on similar charges in 2017 but was acquitted by the High Court for lack of evidence.

President Emmerson Mnangagwa’s government decreed a 150 percent hike in fuel prices last weekend, which triggered the three-day strike, during which protesters barricaded roads with rocks and burnt tyres in the capital Harare. In the second city of Bulawayo, shops were looted.

Police rounded up 600 people, including Mawarire and an opposition legislator, in a crackdown on protesters. A doctors’ group said they had treated 68 people for gunshot wounds.

The Zimbabwe Lawyers for Human Rights, whose lawyers are representing Mawarire and more than 130 others, said police had decided to upgrade the charges against Mawarire.